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The human migration from rural to urban areas has triggered a chain reaction causing the spiking energy demand of cities worldwide. High-rise buildings filling the urban skyline could potentially provide a means to improve the penetration of renewable wind energy by installing wind turbines at their rooftop. However, the above roof flow region has not received much attention and most results deal with low-rise buildings. This study investigates the flow pattern above the roof of a high-rise building by analysing velocity and pressure measurements performed in an atmospheric boundary layer wind tunnel, including four wind directions and two different roof shapes. Comparison of the surface pressure patterns on the flat roof with available low-rise building studies shows that the surface pressure contours are consistent for a given wind direction. At 0° wind direction, a separation bubble is detected, while cone vortices dominate at 30° and 45°. The determining factor for the installation of small wind turbines is the vicinity to the roof. Thus, 45° wind direction shows to be the most desirable angle by bringing the substantial amplification of wind and keeping the turbulence intensity low. Decking the roof creates favourable characteristics by overcoming the sensitivity to the wind direction while preserving the speed-up effect.

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Identification of flutter derivatives by forced vibration testsResults of an experimental study related to flutter phenomenon are presented in the paper. Two cross-sections are considered: a rectangular cross-section and a typical symmetric bridge cross-section. Stationary coefficients and instationary flutter derivatives are determined by means of forced vibration tests. The identification technique is presented in detail. Pressure measurements at the centre of the bridge cross-section are also performed. Main wind flow patterns are analysed based on pressure distribution data. Identifikacija parametara treperenja testovima prisilnih vibracija U radu su prikazani rezultati eksperimentalnog istraživanja vezanoga za pojavu treperenja. Promatrana su dva poprečna presjeka: pravokutan i tipičan simetričan poprečni presjek mosta. Posebno su određeni ustaljeni koeficijenti kao i neustaljeni parametri treperenja primjenom testova prisilnih vibracija. U radu je detaljno prikazana postupak identifikacije. Uz to, na središnjem poprečnom presjeku mosta provedena su mjerenja tlakova. Na osnovi raspodjele tlakova analizirane su glavne sheme obstrujavanja vjetra.